1. Field of the Invention
This invention relates to a drawer, which has metal side walls, delimiting the interior of the drawer on its sides and provided at their top with guide rails, which constitute a part of an extension guide for the drawer, and which have a bottom carrying flange for supporting a bottom plate of the drawer, which carrying flange has stamped out retaining lugs bent up to extend from below into openings of the bottom plate. The drawer also comprises a rear wall mounted between the side walls.
2. Description of the Prior Art
In such drawers the side walls have a multiple function because they limit the drawer on its sides and constitute a part of the extension guide for the drawer and also serve to hold the rear wall of the drawer and optionally to hold a front wall which is provided in most cases in the drawer. The extension guide for the drawer may additionally comprise rollers, which are provided on the side walls and cooperate with guide rails, which are mounted on the body of the furniture. The rear wall of the drawer is usually mounted in such a manner that said rear wall extends as close as possible to the flanges of the side walls of the drawer and the bottom plate abuts the rear wall. The front wall is preferably fixed by means which are as independent as possible from the means for fixing the bottom plate and may comprise adjustable retaining means so that when the drawer has been mounted in a piece of furniture it will be possible to adjust the inclination of the front wall and preferably to make an adjustment to provide gaps of equal width between the front wall and the opening by which the drawer is received or to provide an equal spacing between the edges of the front plate and adjacent drawers.
It is known that the bottom plate may be secured by means of the retaining lugs alone. It has been disclosed in British Patent Specification 2,169,491 that for this purpose the retaining lugs may be bent up about bend lines which are parallel to the longitudinal direction of the flange, the lug-receiving openings are combined to form continuous grooves, which are formed in the bottom plate and are parallel to its edges, and the height of the bent-up retaining lugs is selected to slightly exceed the depth of the narrow groove, which is substantially adapted to the thickness of the lugs, so that the retaining lugs will bite into the bottom of the groove as the bottom plate is forced onto the lugs. But that arrangement will not ensure a satisfactory anchoring of the retaining lugs in the groove so that a lifting of the bottom plate and even a displacement of the bottom plate along the groove will not reliably be prevented. In German Utility Model 86 34 281 it is taught that for this reason in a similar arrangement each retaining lug should be provided at its top with a harpoonlike profile, which will bite into the side face of the groove as the bottom plate is forced onto the retaining lugs. In that case the harpoon head may damage the edge of the groove, the end position of the bottom plate relative to the side walls is not predetermined and the bottom plates may come loose in prolonged use. For this reason it has been proposed in U.S. Pat. No. 4,875,747 that the groove in the bottom plate should be somewhat wider and the correspondingly stamped out retaining lugs should be bent up about bend lines which extend at an acute angle to the longitudinal direction of the flange so that the lugs extend obliquely to the groove and their longitudinal edges will bite into the side faces of the groove as the bottom plate is forced onto the lugs. In all designs which have been described hereinbefore it is possible to fix the bottom plate by simply pressing it against the flanges so that the retaining lugs enter the groove and the assembling is facilitated. But even in the last-mentioned design a lifting of the bottom plate from the carrying flanges is not reliably prevented and the position of the bottom plate which has been forced onto the carrying flanges is not exactly defined so that the use of assembling machines may result in relatively large deviations regarding the fixation of the bottom plate on the side walls. In order to avoid said disadvantages it has been proposed in Published German Application 37 11 063 that retaining lugs should be used which have been bent up parallel to the longitudinal direction of the flange and in order to prevent a displacement in the longitudinal direction should enter associated recesses in the bottom plate and that the bottom plate should be held down forming the side walls above the inserted bottom plate with longitudinal grooves and placing an elastically deformable plastic sheeting on the bottom plate. The plastic sheeting has a protruding edge portion, which snaps into said longitudinal grooves so that said sheeting will hold down the bottom plate. But that design can be used only when the sheeting has been applied and is expensive.
Other means for preventing a lifting of the bottom plate are known from Austrian Patent Specification 388,651 and from Published German Application 38 05 669. In said case the retaining lugs are provided with end claws and are bent up only to such an extent that when the bottom plate has been applied said lugs can be forced into recesses or into a continuous groove formed in the bottom plate. In that case a separate operation requiring special tools, such as pliers, must be performed to bend the lugs further when the bottom plate has been applied so that the claws are then forced into at least one side face of the groove. It is virtually impossible to automate that operation and the afterbending may damage the bottom plate or the retaining lugs and particularly may damage a coating possibly provided on the side walls and retaining lugs so that the side walls if made from a material which does not resist rusting or corrosion may exhibit nonpermissible rust where the side walls are in contact with the lugs. Inter alia, from German Published Application 36 41 325 it is known that the rails of extension guides for the drawers may be secured to the drawer by means of hook-pin joints in an arrangement in which a bent-up hook is provided at the rear end of the guide rail and a pin is provided at the front end, an opening for receiving the hook is formed in the rear wall of a drawer box and an opening for receiving the pin is provided in an edge face of a side wall of the drawer box. In that case the drawer box and the guide rails may be joined in a modular assembly by means of plug joints composed of the stated elements and the plug joints may subsequently be fixed by additionally provided screw joints. If a shorter drawer is to be accommodated in a deeper compartment it will be possible to mount spacers on the guide rails and said spacers may be fixed to the bent-up hooks and may be used to hold down the short drawer by means of a plugged-in pin. It is also known to use a hook-pin joint for the fixation of a wire basket used instead of a drawer box. It is also known from British Patent Specification 2,203,632 to provide a hook-pin joint that comprises a hung-in hook provided at one end of a retaining rail that can be secured to the furniture corpus and a pin that is provided at the other end of the rail and to use that joint for a fixation to the furniture corpus of an extension guide comprising a rail and rollers. Published German Application 37 02 238 discloses the provision of a hook at the rear end of a guide rail to hold down the rear end of a drawer box. In accordance with Austrian Patent Specification 379,497 the corpus rail of an extension guide for a drawer is fixed by a retaining bar, which is provided at its rear end with a hook that has an end leg which has been bent up to extend parallel to a carrying flange, the bar is provided with bent-up retaining lugs spaced from said hook, and the corpus rail has a notch for facilitating the insertion of the hook and openings for receiving the retaining lugs.
It is also known from U.S. Pat. No. 821,576 that the box of a drawer may be assembled from an outer skin of sheet metal and of bottom and wall plates secured to said skin. That outer skin may also extend upwardly over the rear wall of the drawer and has a bent-down top edge portion for retaining a plate which constitutes the rear wall and has bottom edge resting on the bottom plate.